diff --git a/gen/__init__.py b/gen/__init__.py
index df5adf4..87177be 100644
--- a/gen/__init__.py
+++ b/gen/__init__.py
@@ -265,7 +265,7 @@ class Type:
                  editDefault, show, page, group, layouts, move, indexed,
                  searchable, specificReadPermission, specificWritePermission,
                  width, height, colspan, master, masterValue, focus,
-                 historized):
+                 historized, sync):
         # The validator restricts which values may be defined. It can be an
         # interval (1,None), a list of string values ['choice1', 'choice2'],
         # a regular expression, a custom function, a Selection instance, etc.
@@ -349,6 +349,9 @@ class Type:
         # If we must keep track of changes performed on a field, "historized"
         # must be set to True.
         self.historized = historized
+        # self.sync below determines if the field representations will be
+        # retrieved in a synchronous way by the browser or not (Ajax).
+        self.sync = self.formatSync(sync)
         self.id = id(self)
         self.type = self.__class__.__name__
         self.pythonType = None # The True corresponding Python type
@@ -450,6 +453,16 @@ class Type:
         else:
             return self.pageShow
 
+    def formatSync(self, sync):
+        '''Creates a dictionary indicating, for every layout type, if the field
+           value must be retrieved synchronously or not.'''
+        if isinstance(sync, bool):
+            sync = {'edit': sync, 'view': sync, 'cell': sync}
+        for layoutType in ('edit', 'view', 'cell'):
+            if layoutType not in sync:
+                sync[layoutType] = False
+        return sync
+
     def formatLayouts(self, layouts):
         '''Standardizes the given p_layouts. .'''
         # First, get the layouts as a dictionary, if p_layouts is None or
@@ -651,7 +664,7 @@ class Integer(Type):
                       editDefault, show, page, group, layouts, move, indexed,
                       searchable, specificReadPermission,
                       specificWritePermission, width, height, colspan, master,
-                      masterValue, focus, historized)
+                      masterValue, focus, historized, True)
         self.pythonType = long
 
     def validateValue(self, obj, value):
@@ -690,7 +703,7 @@ class Float(Type):
                       editDefault, show, page, group, layouts, move, indexed,
                       False, specificReadPermission, specificWritePermission,
                       width, height, colspan, master, masterValue, focus,
-                      historized)
+                      historized, True)
         self.pythonType = float
 
     def getFormattedValue(self, obj, value):
@@ -851,7 +864,7 @@ class String(Type):
                       editDefault, show, page, group, layouts, move, indexed,
                       searchable, specificReadPermission,
                       specificWritePermission, width, height, colspan, master,
-                      masterValue, focus, historized)
+                      masterValue, focus, historized, True)
         self.isSelect = self.isSelection()
         # Default width and height vary according to String format
         if width == None:
@@ -1016,14 +1029,13 @@ class Boolean(Type):
                       editDefault, show, page, group, layouts, move, indexed,
                       searchable, specificReadPermission,
                       specificWritePermission, width, height, colspan, master,
-                      masterValue, focus, historized)
+                      masterValue, focus, historized, True)
         self.pythonType = bool
 
     def getDefaultLayouts(self):
         return {'view': 'l;f!_', 'edit': Table('f;lrv;=', width=None)}
 
     def getFormattedValue(self, obj, value):
-        if value in nullValues: return ''
         if value: res = obj.translate('yes', domain='plone')
         else:     res = obj.translate('no', domain='plone')
         return res
@@ -1057,7 +1069,7 @@ class Date(Type):
                       editDefault, show, page, group, layouts, move, indexed,
                       searchable, specificReadPermission,
                       specificWritePermission, width, height, colspan, master,
-                      masterValue, focus, historized)
+                      masterValue, focus, historized, True)
 
     def getCss(self, layoutType):
         if layoutType == 'edit': return ('jscalendar/calendar-system.css',)
@@ -1110,7 +1122,7 @@ class File(Type):
                       editDefault, show, page, group, layouts, move, indexed,
                       False, specificReadPermission, specificWritePermission,
                       width, height, colspan, master, masterValue, focus,
-                      historized)
+                      historized, True)
 
     def getValue(self, obj):
         value = Type.getValue(self, obj)
@@ -1209,12 +1221,14 @@ class Ref(Type):
         # filter the list of available tied objects.
         self.select = select
         # Maximum number of referenced objects shown at once.
-        self.maxPerPage = maxPerPage 
+        self.maxPerPage = maxPerPage
+        # Specifies sync
+        sync = {'view': False, 'edit':True}
         Type.__init__(self, validator, multiplicity, index, default, optional,
                       editDefault, show, page, group, layouts, move, indexed,
                       False, specificReadPermission, specificWritePermission,
                       width, height, colspan, master, masterValue, focus,
-                      historized)
+                      historized, sync)
         self.validable = self.link
 
     def getDefaultLayouts(self): return {'view': 'l-f', 'edit': 'lrv-f'}
@@ -1273,7 +1287,7 @@ class Computed(Type):
                  searchable=False, specificReadPermission=False,
                  specificWritePermission=False, width=None, height=None,
                  colspan=1, method=None, plainText=True, master=None,
-                 masterValue=None, focus=False, historized=False):
+                 masterValue=None, focus=False, historized=False, sync=True):
         # The Python method used for computing the field value
         self.method = method
         # Does field computation produce plain text or XHTML?
@@ -1281,7 +1295,8 @@ class Computed(Type):
         Type.__init__(self, None, multiplicity, index, default, optional,
                       False, show, page, group, layouts, move, indexed, False,
                       specificReadPermission, specificWritePermission, width,
-                      height, colspan, master, masterValue, focus, historized)
+                      height, colspan, master, masterValue, focus, historized,
+                      sync)
         self.validable = False
 
     def getValue(self, obj):
@@ -1297,7 +1312,7 @@ class Computed(Type):
             res = str(e)
         return res
 
-    def getFormattedValue(self, obj, value): return self.getValue(obj)
+    def getFormattedValue(self, obj, value): return value
 
 class Action(Type):
     '''An action is a workflow-independent Python method that can be triggered
@@ -1325,7 +1340,8 @@ class Action(Type):
         Type.__init__(self, None, (0,1), index, default, optional,
                       False, show, page, group, layouts, move, indexed, False,
                       specificReadPermission, specificWritePermission, width,
-                      height, colspan, master, masterValue, focus, historized)
+                      height, colspan, master, masterValue, focus, historized,
+                      False)
         self.validable = False
 
     def getDefaultLayouts(self): return {'view': 'l-f', 'edit': 'lrv-f'}
@@ -1377,7 +1393,8 @@ class Info(Type):
         Type.__init__(self, None, (0,1), index, default, optional,
                       False, show, page, group, layouts, move, indexed, False,
                       specificReadPermission, specificWritePermission, width,
-                      height, colspan, master, masterValue, focus, historized)
+                      height, colspan, master, masterValue, focus, historized,
+                      False)
         self.validable = False
 
 class Pod(Type):
@@ -1407,7 +1424,7 @@ class Pod(Type):
                       False, show, page, group, layouts, move, indexed,
                       searchable, specificReadPermission,
                       specificWritePermission, width, height, colspan, master,
-                      masterValue, focus, historized)
+                      masterValue, focus, historized, False)
         self.validable = False
 
 # Workflow-specific types ------------------------------------------------------
diff --git a/gen/plone25/mixins/__init__.py b/gen/plone25/mixins/__init__.py
index 248ef2d..fbeede2 100644
--- a/gen/plone25/mixins/__init__.py
+++ b/gen/plone25/mixins/__init__.py
@@ -300,25 +300,14 @@ class AbstractMixin:
         '''Returns the method named p_methodName.'''
         return getattr(self, methodName, None)
 
-    def getFieldValue(self, name, useParamValue=False, value=None,
-                      formatted=True):
-        '''Returns the value of field named p_name for this object (p_self).
+    def getFieldValue(self, name):
+        '''Returns the database value of field named p_name for p_self.'''
+        return self.getAppyType(name).getValue(self)
 
-           If p_useParamValue is True, the method uses p_value instead of the
-           real field value (useful for rendering a value from the object
-           history, for example).
-
-           If p_formatted is False, it will return the true database
-           (or default) value. Else, it will produce a nice, string and
-           potentially translated value.'''
-        appyType = self.getAppyType(name)
-        # Which value will we use ?
-        if not useParamValue:
-            value = appyType.getValue(self)
-        # Return the value as is if it is None or forMasterId
-        if not formatted: return value
-        # Return the formatted value else
-        return appyType.getFormattedValue(self, value)
+    def getFormattedFieldValue(self, name, value):
+        '''Gets a nice, string representation of p_value which is a value from
+           field named p_name.'''
+        return self.getAppyType(name).getFormattedValue(self, value)
 
     def _appy_getRefs(self, fieldName, ploneObjects=False,
                       noListIfSingleObj=False, startNumber=None):
diff --git a/gen/plone25/model.py b/gen/plone25/model.py
index fe7758f..e53169c 100644
--- a/gen/plone25/model.py
+++ b/gen/plone25/model.py
@@ -22,7 +22,7 @@ class ModelClass:
     _appy_notinit = ('id', 'type', 'pythonType', 'slaves', 'phase', 'pageShow',
                      'isSelect', 'hasLabel', 'hasDescr', 'hasHelp',
                      'master_css', 'layouts', 'required', 'filterable',
-                     'validable', 'backd', 'isBack')
+                     'validable', 'backd', 'isBack', 'sync')
 
     @classmethod
     def _appy_addField(klass, fieldName, fieldType, classDescr):
diff --git a/gen/plone25/skin/page.pt b/gen/plone25/skin/page.pt
index fb60a66..0aa3571 100644
--- a/gen/plone25/skin/page.pt
+++ b/gen/plone25/skin/page.pt
@@ -157,6 +157,12 @@
     }
     askAjaxChunk(hookId, 'GET', objectUrl, 'widgets/ref', 'viewContent',params);
   }
+  function askComputedField(hookId, objectUrl, fieldName) {
+    // Sends an Ajax request for getting the content of a computed field
+    var params = {'fieldName': fieldName};
+    askAjaxChunk(hookId, 'GET', objectUrl, 'widgets/computed', 'viewContent',
+                 params);
+  }
 
   // Function used by checkbox widgets for having radio-button-like behaviour
   function toggleCheckbox(visibleCheckbox, hiddenBoolean) {
@@ -455,7 +461,7 @@
           </tr>
           <tr tal:repeat="change event/changes/items" valign="top">
             <td tal:content="python: tool.translate(change[1][1])"></td>
-            <td tal:define="appyValue python: contextObj.getFieldValue(change[0], useParamValue=True, value=change[1][0]);
+            <td tal:define="appyValue python: contextObj.getFormattedFieldValue(change[0], change[1][0]);
                             appyType python:contextObj.getAppyType(change[0], asDict=True);
                             severalValues python: (appyType['multiplicity'][1] &gt; 1) or (appyType['multiplicity'][1] == None)">
               <span tal:condition="not: severalValues" tal:replace="appyValue"></span>
diff --git a/gen/plone25/skin/widgets/computed.pt b/gen/plone25/skin/widgets/computed.pt
index 23a0a8e..e0acae4 100644
--- a/gen/plone25/skin/widgets/computed.pt
+++ b/gen/plone25/skin/widgets/computed.pt
@@ -1,7 +1,26 @@
 <tal:comment replace="nothing">View macro for a Computed.</tal:comment>
 <metal:view define-macro="view">
-  <span tal:condition="widget/plainText" tal:replace="value"/>
-  <span tal:condition="not: widget/plainText" tal:replace="structure value"/>
+  <tal:sync condition="sync">
+    <span tal:condition="widget/plainText" tal:replace="value"/>
+    <span tal:condition="not: widget/plainText" tal:replace="structure value"/>
+  </tal:sync>
+  <tal:async condition="not: sync">
+    <div tal:define= "ajaxHookId python: contextObj.UID() + name"
+         tal:attributes = "id ajaxHookId">
+      <script language="javascript"
+          tal:content="python: 'askComputedField(\'%s\',\'%s\',\'%s\')' % (ajaxHookId, contextObj.absolute_url(), name)">
+      </script>
+    </div>
+  </tal:async>
+</metal:view>
+
+<tal:comment replace="nothing">Ajax-called view content of a non sync Computed field.</tal:comment>
+<metal:view define-macro="viewContent"
+            tal:define="name request/fieldName;
+                        widget python: contextObj.getAppyType(name, asDict=True);
+                        value python: contextObj.getFieldValue(name);
+                        sync python:True">
+  <metal:call use-macro="portal/skyn/widgets/computed/macros/view"/>
 </metal:view>
 
 <tal:comment replace="nothing">Edit macro for a Computed.</tal:comment>
diff --git a/gen/plone25/skin/widgets/show.pt b/gen/plone25/skin/widgets/show.pt
index ae172b2..c2717c7 100644
--- a/gen/plone25/skin/widgets/show.pt
+++ b/gen/plone25/skin/widgets/show.pt
@@ -54,8 +54,9 @@
        tal:define="contextMacro    python: portal.skyn.widgets;
                    layout          python: widget['layouts'][layoutType];
                    name            widget/name;
-                   value           python: contextObj.getFieldValue(name);
-                   rawValue        python: contextObj.getFieldValue(name, formatted=False);
+                   sync            python: widget['sync'][layoutType];
+                   rawValue        python: sync and contextObj.getFieldValue(name) or None;
+                   value           python: sync and contextObj.getFormattedFieldValue(name, rawValue) or None;
                    requestValue    python: request.get(name, None);
                    inRequest       python: request.has_key(name);
                    errors          errors | python: ();